Thanks again for Peter Diehl for his help with this one.  Greenpeace have collected and released some oblique aerial images of the site at Ajkai Timfoldgyar (Kolontar) that are revealing.  They are available on the Der Standard website.  The best image of the dam itself is this one:

Note the crack in the dam surface on the left side of the image. It is also worth noting that the dam structure on the left side of the breach is rather different from that on the right.   Finally, note the interesting shape of the fracture on the left side of the breach.  I continue to be interested in the foundation of this structure, although I would also be interested to know a little more about the transition between the dam structure on the left side and that on the right side of the breach.

Meanwhile, Peter has also tracked down the aerial video imagery of the breach.  This can be accessed here.